ip_vs_ctl.c

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/*
 * IPVS         An implementation of the IP virtual server support for the
 *              LINUX operating system.  IPVS is now implemented as a module
 *              over the NetFilter framework. IPVS can be used to build a
 *              high-performance and highly available server based on a
 *              cluster of servers.
 *
 * Version:     $Id: ip_vs_ctl.c,v 1.30.2.3 2003/07/29 14:37:12 wensong Exp $
 *
 * Authors:     Wensong Zhang <wensong@linuxvirtualserver.org>
 *              Peter Kese <peter.kese@ijs.si>
 *              Julian Anastasov <ja@ssi.bg>
 *
 *              This program is free software; you can redistribute it and/or
 *              modify it under the terms of the GNU General Public License
 *              as published by the Free Software Foundation; either version
 *              2 of the License, or (at your option) any later version.
 *
 * Changes:
 *
 */

#include <linux/config.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/init.h>
#include <linux/types.h>
#include <linux/errno.h>
#include <linux/fs.h>
#include <linux/sysctl.h>
#include <linux/proc_fs.h>
#include <linux/timer.h>
#include <linux/swap.h>
#include <linux/proc_fs.h>

#include <linux/netfilter.h>
#include <linux/netfilter_ipv4.h>

#include <net/ip.h>
#include <net/sock.h>

#include <asm/uaccess.h>

#include <net/ip_vs.h>

/* semaphore for IPVS sockopts. And, [gs]etsockopt may sleep. */
static DECLARE_MUTEX(__ip_vs_mutex);

/* lock for service table */
rwlock_t __ip_vs_svc_lock = RW_LOCK_UNLOCKED;

/* lock for table with the real services */
static rwlock_t __ip_vs_rs_lock = RW_LOCK_UNLOCKED;

/* lock for state and timeout tables */
static rwlock_t __ip_vs_securetcp_lock = RW_LOCK_UNLOCKED;

/* lock for drop entry handling */
static spinlock_t __ip_vs_dropentry_lock = SPIN_LOCK_UNLOCKED;

/* lock for drop packet handling */
static spinlock_t __ip_vs_droppacket_lock = SPIN_LOCK_UNLOCKED;

/* 1/rate drop and drop-entry variables */
int ip_vs_drop_rate = 0;
int ip_vs_drop_counter = 0;
atomic_t ip_vs_dropentry = ATOMIC_INIT(0);

/* number of virtual services */
static int ip_vs_num_services = 0;

/* sysctl variables */
static int sysctl_ip_vs_drop_entry = 0;
static int sysctl_ip_vs_drop_packet = 0;
static int sysctl_ip_vs_secure_tcp = 0;
static int sysctl_ip_vs_amemthresh = 2048;
static int sysctl_ip_vs_am_droprate = 10;
int sysctl_ip_vs_cache_bypass = 0;
int sysctl_ip_vs_expire_nodest_conn = 0;
int sysctl_ip_vs_sync_threshold = 3;
int sysctl_ip_vs_nat_icmp_send = 0;

#ifdef CONFIG_IP_VS_DEBUG
static int sysctl_ip_vs_debug_level = 0;

int ip_vs_get_debug_level(void)
{
        return sysctl_ip_vs_debug_level;
}
#endif

/*
 *      update_defense_level is called from timer bh and from sysctl.
 */
static void update_defense_level(void)
{
        struct sysinfo i;
        int availmem;
        int nomem;

        /* we only count free and buffered memory (in pages) */
        si_meminfo(&i);
        availmem = i.freeram + i.bufferram;

        nomem = (availmem < sysctl_ip_vs_amemthresh);

        /* drop_entry */
        spin_lock(&__ip_vs_dropentry_lock);
        switch (sysctl_ip_vs_drop_entry) {
        case 0:
                atomic_set(&ip_vs_dropentry, 0);
                break;
        case 1:
                if (nomem) {
                        atomic_set(&ip_vs_dropentry, 1);
                        sysctl_ip_vs_drop_entry = 2;
                } else {
                        atomic_set(&ip_vs_dropentry, 0);
                }
                break;
        case 2:
                if (nomem) {
                        atomic_set(&ip_vs_dropentry, 1);
                } else {
                        atomic_set(&ip_vs_dropentry, 0);
                        sysctl_ip_vs_drop_entry = 1;
                };
                break;
        case 3:
                atomic_set(&ip_vs_dropentry, 1);
                break;
        }
        spin_unlock(&__ip_vs_dropentry_lock);

        /* drop_packet */
        spin_lock(&__ip_vs_droppacket_lock);
        switch (sysctl_ip_vs_drop_packet) {
        case 0:
                ip_vs_drop_rate = 0;
                break;
        case 1:
                if (nomem) {
                        ip_vs_drop_rate = ip_vs_drop_counter
                                = sysctl_ip_vs_amemthresh /
                                (sysctl_ip_vs_amemthresh - availmem);
                        sysctl_ip_vs_drop_packet = 2;
                } else {
                        ip_vs_drop_rate = 0;
                }
                break;
        case 2:
                if (nomem) {
                        ip_vs_drop_rate = ip_vs_drop_counter
                                = sysctl_ip_vs_amemthresh /
                                (sysctl_ip_vs_amemthresh - availmem);
                } else {
                        ip_vs_drop_rate = 0;
                        sysctl_ip_vs_drop_packet = 1;
                }
                break;
        case 3:
                ip_vs_drop_rate = sysctl_ip_vs_am_droprate;
                break;
        }
        spin_unlock(&__ip_vs_droppacket_lock);

        /* secure_tcp */
        write_lock(&__ip_vs_securetcp_lock);
        switch (sysctl_ip_vs_secure_tcp) {
        case 0:
                ip_vs_secure_tcp_set(0);
                break;
        case 1:
                if (nomem) {
                        ip_vs_secure_tcp_set(1);
                        sysctl_ip_vs_secure_tcp = 2;
                } else {
                        ip_vs_secure_tcp_set(0);
                }
                break;
        case 2:
                if (nomem) {
                        ip_vs_secure_tcp_set(1);
                } else {
                        ip_vs_secure_tcp_set(0);
                        sysctl_ip_vs_secure_tcp = 1;
                }
                break;
        case 3:
                ip_vs_secure_tcp_set(1);
                break;
        }
        write_unlock(&__ip_vs_securetcp_lock);
}


/*
 *      Timer for checking the defense
 */
static struct timer_list defense_timer;
#define DEFENSE_TIMER_PERIOD    1*HZ

static void defense_timer_handler(unsigned long data)
{
        update_defense_level();
        if (atomic_read(&ip_vs_dropentry))
                ip_vs_random_dropentry();

        mod_timer(&defense_timer, jiffies + DEFENSE_TIMER_PERIOD);
}


/*
 *  Hash table: for virtual service lookups
 */
#define IP_VS_SVC_TAB_BITS 8
#define IP_VS_SVC_TAB_SIZE (1 << IP_VS_SVC_TAB_BITS)
#define IP_VS_SVC_TAB_MASK (IP_VS_SVC_TAB_SIZE - 1)

/* the service table hashed by <protocol, addr, port> */
static struct list_head ip_vs_svc_table[IP_VS_SVC_TAB_SIZE];
/* the service table hashed by fwmark */
static struct list_head ip_vs_svc_fwm_table[IP_VS_SVC_TAB_SIZE];

/*
 *  Hash table: for real service lookups
 */
#define IP_VS_RTAB_BITS 4
#define IP_VS_RTAB_SIZE (1 << IP_VS_RTAB_BITS)
#define IP_VS_RTAB_MASK (IP_VS_RTAB_SIZE - 1)

static struct list_head ip_vs_rtable[IP_VS_RTAB_SIZE];

/*
 * Trash for destinations
 */
static LIST_HEAD(ip_vs_dest_trash);

/*
 * FTP & NULL virtual service counters
 */
static atomic_t ip_vs_ftpsvc_counter = ATOMIC_INIT(0);
static atomic_t ip_vs_nullsvc_counter = ATOMIC_INIT(0);


/*
 *  Returns hash value for virtual service
 */
static __inline__ unsigned
ip_vs_svc_hashkey(unsigned proto, __u32 addr, __u16 port)
{
        register unsigned porth = ntohs(port);

        return (proto^ntohl(addr)^(porth>>IP_VS_SVC_TAB_BITS)^porth)
                & IP_VS_SVC_TAB_MASK;
}

/*
 *  Returns hash value of fwmark for virtual service lookup
 */
static __inline__ unsigned ip_vs_svc_fwm_hashkey(__u32 fwmark)
{
        return fwmark & IP_VS_SVC_TAB_MASK;
}

/*
 *  Hashes ip_vs_service in the ip_vs_svc_table by <proto,addr,port>
 *  or in the ip_vs_svc_fwm_table by fwmark.
 *  Should be called with locked tables.
 *  Returns bool success.
 */
static int ip_vs_svc_hash(struct ip_vs_service *svc)
{
        unsigned hash;

        if (svc->flags & IP_VS_SVC_F_HASHED) {
                IP_VS_ERR("ip_vs_svc_hash(): request for already hashed, "
                          "called from %p\n", __builtin_return_address(0));
                return 0;
        }

        if (svc->fwmark == 0) {
                /*
                 *  Hash it by <protocol,addr,port> in ip_vs_svc_table
                 */
                hash = ip_vs_svc_hashkey(svc->protocol, svc->addr, svc->port);
                list_add(&svc->s_list, &ip_vs_svc_table[hash]);
        } else {
                /*
                 *  Hash it by fwmark in ip_vs_svc_fwm_table
                 */
                hash = ip_vs_svc_fwm_hashkey(svc->fwmark);
                list_add(&svc->f_list, &ip_vs_svc_fwm_table[hash]);
        }

        svc->flags |= IP_VS_SVC_F_HASHED;
        /* increase its refcnt because it is referenced by the svc table */
        atomic_inc(&svc->refcnt);
        return 1;
}


/*
 *  Unhashes ip_vs_service from ip_vs_svc_table/ip_vs_svc_fwm_table.
 *  Should be called with locked tables.
 *  Returns bool success.
 */
static int ip_vs_svc_unhash(struct ip_vs_service *svc)
{
        if (!(svc->flags & IP_VS_SVC_F_HASHED)) {
                IP_VS_ERR("ip_vs_svc_unhash(): request for unhash flagged, "
                          "called from %p\n", __builtin_return_address(0));
                return 0;
        }

        if (svc->fwmark == 0) {
                /*
                 * Remove it from the ip_vs_svc_table table.
                 */
                list_del(&svc->s_list);
        } else {
                /*
                 * Remove it from the ip_vs_svc_fwm_table table.
                 */
                list_del(&svc->f_list);
        }

        svc->flags &= ~IP_VS_SVC_F_HASHED;
        atomic_dec(&svc->refcnt);
        return 1;
}


/*
 *  Get service by {proto,addr,port} in the service table.
 */
static __inline__ struct ip_vs_service *
__ip_vs_service_get(__u16 protocol, __u32 vaddr, __u16 vport)
{
        unsigned hash;
        struct ip_vs_service *svc;
        struct list_head *l,*e;

        /*
         *      Check for "full" addressed entries
         */
        hash = ip_vs_svc_hashkey(protocol, vaddr, vport);

        l = &ip_vs_svc_table[hash];
        for (e=l->next; e!=l; e=e->next) {
                svc = list_entry(e, struct ip_vs_service, s_list);
                if ((svc->addr == vaddr)
                    && (svc->port == vport)
                    && (svc->protocol == protocol)) {
                        /* HIT */
                        atomic_inc(&svc->usecnt);
                        return svc;
                }
        }

        return NULL;
}


/*
 *  Get service by {fwmark} in the service table.
 */
static __inline__ struct ip_vs_service *__ip_vs_svc_fwm_get(__u32 fwmark)
{
        unsigned hash;
        struct ip_vs_service *svc;
        struct list_head *l,*e;

        /*
         *      Check for "full" addressed entries
         */
        hash = ip_vs_svc_fwm_hashkey(fwmark);

        l = &ip_vs_svc_fwm_table[hash];
        for (e=l->next; e!=l; e=e->next) {
                svc = list_entry(e, struct ip_vs_service, f_list);
                if (svc->fwmark == fwmark) {
                        /* HIT */
                        atomic_inc(&svc->usecnt);
                        return svc;
                }
        }

        return NULL;
}

struct ip_vs_service *
ip_vs_service_get(__u32 fwmark, __u16 protocol, __u32 vaddr, __u16 vport)
{
        struct ip_vs_service *svc;

        read_lock(&__ip_vs_svc_lock);

        /*
         *      Check the table hashed by fwmark first
         */
        if (fwmark && (svc = __ip_vs_svc_fwm_get(fwmark)))
                goto out;

        /*
         *      Check the table hashed by <protocol,addr,port>
         *      for "full" addressed entries
         */
        svc = __ip_vs_service_get(protocol, vaddr, vport);

        if (svc == NULL
            && protocol == IPPROTO_TCP
            && atomic_read(&ip_vs_ftpsvc_counter)
            && (vport == FTPDATA || ntohs(vport) >= PROT_SOCK)) {
                /*
                 * Check if ftp service entry exists, the packet
                 * might belong to FTP data connections.
                 */
                svc = __ip_vs_service_get(protocol, vaddr, FTPPORT);
        }

        if (svc == NULL
            && atomic_read(&ip_vs_nullsvc_counter)) {
                /*
                 * Check if the catch-all port (port zero) exists
                 */
                svc = __ip_vs_service_get(protocol, vaddr, 0);
        }

  out:
        read_unlock(&__ip_vs_svc_lock);

        IP_VS_DBG(6, "lookup service: fwm %u %s %u.%u.%u.%u:%u %s\n",
                  fwmark, ip_vs_proto_name(protocol),
                  NIPQUAD(vaddr), ntohs(vport),
                  svc?"hit":"not hit");

        return svc;
}


static inline void
__ip_vs_bind_svc(struct ip_vs_dest *dest, struct ip_vs_service *svc)
{
        atomic_inc(&svc->refcnt);
        dest->svc = svc;
}

static inline void
__ip_vs_unbind_svc(struct ip_vs_dest *dest)
{
        struct ip_vs_service *svc = dest->svc;

        dest->svc = NULL;
        if (atomic_dec_and_test(&svc->refcnt))
                kfree(svc);
}

/*
 *  Returns hash value for real service
 */
static __inline__ unsigned ip_vs_rs_hashkey(__u32 addr, __u16 port)
{
        register unsigned porth = ntohs(port);

        return (ntohl(addr)^(porth>>IP_VS_RTAB_BITS)^porth)
                & IP_VS_RTAB_MASK;
}

/*
 *  Hashes ip_vs_dest in ip_vs_rtable by proto,addr,port.
 *  should be called with locked tables.
 *  returns bool success.
 */
static int ip_vs_rs_hash(struct ip_vs_dest *dest)
{
        unsigned hash;

        if (!list_empty(&dest->d_list)) {
                return 0;
        }

        /*
         *      Hash by proto,addr,port,
         *      which are the parameters of the real service.
         */
        hash = ip_vs_rs_hashkey(dest->addr, dest->port);
        list_add(&dest->d_list, &ip_vs_rtable[hash]);

        return 1;
}

/*
 *  UNhashes ip_vs_dest from ip_vs_rtable.
 *  should be called with locked tables.
 *  returns bool success.
 */
static int ip_vs_rs_unhash(struct ip_vs_dest *dest)
{
        /*
         * Remove it from the ip_vs_rtable table.
         */
        if (!list_empty(&dest->d_list)) {
                list_del(&dest->d_list);
                INIT_LIST_HEAD(&dest->d_list);
        }

        return 1;
}

/*
 *  Lookup real service by {proto,addr,port} in the real service table.
 */
struct ip_vs_dest *
ip_vs_lookup_real_service(__u16 protocol, __u32 daddr, __u16 dport)
{
        unsigned hash;
        struct ip_vs_dest *dest;
        struct list_head *l,*e;

        /*
         *      Check for "full" addressed entries
         *      Return the first found entry
         */
        hash = ip_vs_rs_hashkey(daddr, dport);

        l = &ip_vs_rtable[hash];

        read_lock(&__ip_vs_rs_lock);
        for (e=l->next; e!=l; e=e->next) {
                dest = list_entry(e, struct ip_vs_dest, d_list);
                if ((dest->addr == daddr)
                    && (dest->port == dport)
                    && ((dest->protocol == protocol) ||
                        dest->vfwmark)) {
                        /* HIT */
                        read_unlock(&__ip_vs_rs_lock);
                        return dest;
                }
        }
        read_unlock(&__ip_vs_rs_lock);

        return NULL;
}

/*
 *  Lookup destination by {addr,port} in the given service
 */
static struct ip_vs_dest *
ip_vs_lookup_dest(struct ip_vs_service *svc, __u32 daddr, __u16 dport)
{
        struct ip_vs_dest *dest;
        struct list_head *l, *e;

        /*
         * Find the destination for the given service
         */
        l = &svc->destinations;
        for (e=l->next; e!=l; e=e->next) {
                dest = list_entry(e, struct ip_vs_dest, n_list);
                if ((dest->addr == daddr) && (dest->port == dport)) {
                        /* HIT */
                        return dest;
                }
        }

        return NULL;
}


/*
 *  Lookup dest by {svc,addr,port} in the destination trash.
 *  The destination trash is used to hold the destinations that are removed
 *  from the service table but are still referenced by some conn entries.
 *  The reason to add the destination trash is when the dest is temporary
 *  down (either by administrator or by monitor program), the dest can be
 *  picked back from the trash, the remaining connections to the dest can
 *  continue, and the counting information of the dest is also useful for
 *  scheduling.
 */
static struct ip_vs_dest *
ip_vs_trash_get_dest(struct ip_vs_service *svc, __u32 daddr, __u16 dport)
{
        struct ip_vs_dest *dest;
        struct list_head *l, *e;

        /*
         * Find the destination in trash
         */
        l = &ip_vs_dest_trash;

        for (e=l->next; e!=l; e=e->next) {
                dest = list_entry(e, struct ip_vs_dest, n_list);
                IP_VS_DBG(3, "Destination %u/%u.%u.%u.%u:%u still in trash, "
                          "refcnt=%d\n",
                          dest->vfwmark,
                          NIPQUAD(dest->addr), ntohs(dest->port),
                          atomic_read(&dest->refcnt));
                if (dest->addr == daddr &&
                    dest->port == dport &&
                    dest->vfwmark == svc->fwmark &&
                    dest->protocol == svc->protocol &&
                    (svc->fwmark ||
                     (dest->vaddr == svc->addr &&
                      dest->vport == svc->port))) {
                        /* HIT */
                        return dest;
                }

                /*
                 * Try to purge the destination from trash if not referenced
                 */
                if (atomic_read(&dest->refcnt) == 1) {
                        IP_VS_DBG(3, "Removing destination %u/%u.%u.%u.%u:%u "
                                  "from trash\n",
                                  dest->vfwmark,
                                  NIPQUAD(dest->addr), ntohs(dest->port));
                        e = e->prev;
                        list_del(&dest->n_list);
                        __ip_vs_dst_reset(dest);
                        __ip_vs_unbind_svc(dest);
                        kfree(dest);
                }
        }

        return NULL;
}


/*
 *  Clean up all the destinations in the trash
 *  Called by the ip_vs_control_cleanup()
 *
 *  When the ip_vs_control_clearup is activated by ipvs module exit,
 *  the service tables must have been flushed and all the connections
 *  are expired, and the refcnt of each destination in the trash must
 *  be 1, so we simply release them here.
 */
static void ip_vs_trash_cleanup(void)
{
        struct ip_vs_dest *dest;
        struct list_head *l;

        l = &ip_vs_dest_trash;

        while (l->next != l) {
                dest = list_entry(l->next, struct ip_vs_dest, n_list);
                list_del(&dest->n_list);
                __ip_vs_dst_reset(dest);
                __ip_vs_unbind_svc(dest);
                kfree(dest);
        }
}


static inline void
__ip_vs_zero_stats(struct ip_vs_stats *stats)
{
        spin_lock_bh(&stats->lock);
        memset(stats, 0, (char *)&stats->lock - (char *)stats);
        spin_unlock_bh(&stats->lock);
        ip_vs_zero_estimator(stats);
}

/*
 *  Update a destination in the given service
 */
static void __ip_vs_update_dest(struct ip_vs_service *svc,
                                struct ip_vs_dest *dest,
                                struct ip_vs_rule_user *ur)
{
        int conn_flags;

        /*
         *    Set the weight and the flags
         */
        atomic_set(&dest->weight, ur->weight);

        conn_flags = ur->conn_flags | IP_VS_CONN_F_INACTIVE;

        /*
         *    Check if local node and update the flags
         */
        if (inet_addr_type(ur->daddr) == RTN_LOCAL) {
                conn_flags = (conn_flags & ~IP_VS_CONN_F_FWD_MASK)
                        | IP_VS_CONN_F_LOCALNODE;
        }

        /*
         *    Set the IP_VS_CONN_F_NOOUTPUT flag if not masquerading
         */
        if ((conn_flags & IP_VS_CONN_F_FWD_MASK) != 0) {
                conn_flags |= IP_VS_CONN_F_NOOUTPUT;
        } else {
                /*
                 *    Put the real service in ip_vs_rtable if not present.
                 *    For now only for NAT!
                 */
                write_lock_bh(&__ip_vs_rs_lock);
                ip_vs_rs_hash(dest);
                write_unlock_bh(&__ip_vs_rs_lock);
        }
        atomic_set(&dest->conn_flags, conn_flags);

        /* bind the service */
        if (!dest->svc) {
                __ip_vs_bind_svc(dest, svc);
        } else {
                if (dest->svc != svc) {
                        __ip_vs_unbind_svc(dest);
                        __ip_vs_zero_stats(&dest->stats);
                        __ip_vs_bind_svc(dest, svc);
                }
        }

        /* set the dest status flags */
        dest->flags |= IP_VS_DEST_F_AVAILABLE;
}


/*
 *  Create a destination for the given service
 */
static int
ip_vs_new_dest(struct ip_vs_service *svc, struct ip_vs_rule_user *ur,
               struct ip_vs_dest **destp)
{
        struct ip_vs_dest *dest;
        unsigned atype;

        EnterFunction(2);

        atype = inet_addr_type(ur->daddr);
        if (atype != RTN_LOCAL && atype != RTN_UNICAST)
                return -EINVAL;

        *destp = dest = (struct ip_vs_dest*)
                kmalloc(sizeof(struct ip_vs_dest), GFP_ATOMIC);
        if (dest == NULL) {
                IP_VS_ERR("ip_vs_new_dest: kmalloc failed.\n");
                return -ENOMEM;
        }
        memset(dest, 0, sizeof(struct ip_vs_dest));

        dest->protocol = svc->protocol;
        dest->vaddr = svc->addr;
        dest->vport = svc->port;
        dest->vfwmark = svc->fwmark;
        dest->addr = ur->daddr;
        dest->port = ur->dport;

        atomic_set(&dest->activeconns, 0);
        atomic_set(&dest->inactconns, 0);
        atomic_set(&dest->refcnt, 0);

        INIT_LIST_HEAD(&dest->d_list);
        dest->dst_lock = SPIN_LOCK_UNLOCKED;
        dest->stats.lock = SPIN_LOCK_UNLOCKED;
        __ip_vs_update_dest(svc, dest, ur);
        ip_vs_new_estimator(&dest->stats);

        LeaveFunction(2);
        return 0;
}


/*
 *  Add a destination into an existing service
 */
static int ip_vs_add_dest(struct ip_vs_service *svc,
                          struct ip_vs_rule_user *ur)
{
        struct ip_vs_dest *dest;
        __u32 daddr = ur->daddr;
        __u16 dport = ur->dport;
        int ret;

        EnterFunction(2);

        if (ur->weight < 0) {
                IP_VS_ERR("ip_vs_add_dest(): server weight less than zero\n");
                return -ERANGE;
        }

        /*
         * Check if the dest already exists in the list
         */
        dest = ip_vs_lookup_dest(svc, daddr, dport);
        if (dest != NULL) {
                IP_VS_DBG(1, "ip_vs_add_dest(): dest already exists\n");
                return -EEXIST;
        }

        /*
         * Check if the dest already exists in the trash and
         * is from the same service
         */
        dest = ip_vs_trash_get_dest(svc, daddr, dport);
        if (dest != NULL) {
                IP_VS_DBG(3, "Get destination %u.%u.%u.%u:%u from trash, "
                          "refcnt=%d, service %u/%u.%u.%u.%u:%u\n",
                          NIPQUAD(daddr), ntohs(dport),
                          atomic_read(&dest->refcnt),
                          dest->vfwmark,
                          NIPQUAD(dest->vaddr),
                          ntohs(dest->vport));
                __ip_vs_update_dest(svc, dest, ur);

                /*
                 * Get the destination from the trash
                 */
                list_del(&dest->n_list);

                ip_vs_new_estimator(&dest->stats);

                write_lock_bh(&__ip_vs_svc_lock);

                /*
                 * Wait until all other svc users go away.
                 */
                while (atomic_read(&svc->usecnt) > 1) {};

                list_add(&dest->n_list, &svc->destinations);
                svc->num_dests++;

                /* call the update_service function of its scheduler */
                svc->scheduler->update_service(svc);

                write_unlock_bh(&__ip_vs_svc_lock);
                return 0;
        }

        /*
         * Allocate and initialize the dest structure
         */
        ret = ip_vs_new_dest(svc, ur, &dest);
        if (ret) {
                return ret;
        }

        /*
         * Add the dest entry into the list
         */
        atomic_inc(&dest->refcnt);

        write_lock_bh(&__ip_vs_svc_lock);

        /*
         * Wait until all other svc users go away.
         */
        while (atomic_read(&svc->usecnt) > 1) {};

        list_add(&dest->n_list, &svc->destinations);
        svc->num_dests++;

        /* call the update_service function of its scheduler */
        svc->scheduler->update_service(svc);

        write_unlock_bh(&__ip_vs_svc_lock);

        LeaveFunction(2);

        return 0;
}


/*
 *  Edit a destination in the given service
 */
static int ip_vs_edit_dest(struct ip_vs_service *svc,
                           struct ip_vs_rule_user *ur)
{
        struct ip_vs_dest *dest;
        __u32 daddr = ur->daddr;
        __u16 dport = ur->dport;

        EnterFunction(2);

        if (ur->weight < 0) {
                IP_VS_ERR("ip_vs_edit_dest(): server weight less than zero\n");
                return -ERANGE;
        }

        /*
         *  Lookup the destination list
         */
        dest = ip_vs_lookup_dest(svc, daddr, dport);
        if (dest == NULL) {
                IP_VS_DBG(1, "ip_vs_edit_dest(): dest doesn't exist\n");
                return -ENOENT;
        }

        __ip_vs_update_dest(svc, dest, ur);

        /* call the update_service, because server weight may be changed */
        svc->scheduler->update_service(svc);

        LeaveFunction(2);

        return 0;
}


/*
 *  Delete a destination (must be already unlinked from the service)
 */
static void __ip_vs_del_dest(struct ip_vs_dest *dest)
{
        ip_vs_kill_estimator(&dest->stats);

        /*
         *  Remove it from the d-linked list with the real services.
         */
        write_lock_bh(&__ip_vs_rs_lock);
        ip_vs_rs_unhash(dest);
        write_unlock_bh(&__ip_vs_rs_lock);

        /*
         *  Decrease the refcnt of the dest, and free the dest
         *  if nobody refers to it (refcnt=0). Otherwise, throw
         *  the destination into the trash.
         */
        if (atomic_dec_and_test(&dest->refcnt)) {
                __ip_vs_dst_reset(dest);
                /* simply decrease svc->refcnt here, let the caller check
                   and release the service if nobody refers to it.
                   Only user context can release destination and service,
                   and only one user context can update virtual service at a
                   time, so the operation here is OK */
                atomic_dec(&dest->svc->refcnt);
                kfree(dest);
        } else {
                IP_VS_DBG(3, "Moving dest %u.%u.%u.%u:%u into trash, refcnt=%d\n",
                          NIPQUAD(dest->addr), ntohs(dest->port),
                          atomic_read(&dest->refcnt));
                list_add(&dest->n_list, &ip_vs_dest_trash);
                atomic_inc(&dest->refcnt);
        }
}


/*
 *  Unlink a destination from the given service
 */
static void __ip_vs_unlink_dest(struct ip_vs_service *svc,
                                struct ip_vs_dest *dest,
                                int svcupd)
{
        dest->flags &= ~IP_VS_DEST_F_AVAILABLE;

        /*
         *  Remove it from the d-linked destination list.
         */
        list_del(&dest->n_list);
        svc->num_dests--;
        if (svcupd) {
                /*
                 *  Call the update_service function of its scheduler
                 */
                svc->scheduler->update_service(svc);
        }
}


/*
 *  Delete a destination server in the given service
 */
static int ip_vs_del_dest(struct ip_vs_service *svc,struct ip_vs_rule_user *ur)
{
        struct ip_vs_dest *dest;
        __u32 daddr = ur->daddr;
        __u16 dport = ur->dport;

        EnterFunction(2);

        dest = ip_vs_lookup_dest(svc, daddr, dport);
        if (dest == NULL) {
                IP_VS_DBG(1, "ip_vs_del_dest(): destination not found!\n");
                return -ENOENT;
        }

        write_lock_bh(&__ip_vs_svc_lock);

        /*
         *      Wait until all other svc users go away.
         */
        while (atomic_read(&svc->usecnt) > 1) {};

        /*
         *      Unlink dest from the service
         */
        __ip_vs_unlink_dest(svc, dest, 1);

        write_unlock_bh(&__ip_vs_svc_lock);

        /*
         *      Delete the destination
         */
        __ip_vs_del_dest(dest);

        LeaveFunction(2);

        return 0;
}


/*
 *  Add a service into the service hash table
 */
static int
ip_vs_add_service(struct ip_vs_rule_user *ur, struct ip_vs_service **svc_p)
{
        int ret = 0;
        struct ip_vs_scheduler *sched;
        struct ip_vs_service *svc = NULL;

        MOD_INC_USE_COUNT;

        /*
         * Lookup the scheduler, by 'ur->sched_name'
         */
        sched = ip_vs_scheduler_get(ur->sched_name);
        if (sched == NULL) {
                IP_VS_INFO("Scheduler module ip_vs_%s.o not found\n",
                           ur->sched_name);
                ret = -ENOENT;
                goto out_mod_dec;
        }

        svc = (struct ip_vs_service*)
                kmalloc(sizeof(struct ip_vs_service), GFP_ATOMIC);
        if (svc == NULL) {
                IP_VS_DBG(1, "ip_vs_add_service: kmalloc failed.\n");
                ret = -ENOMEM;
                goto out_err;
        }
        memset(svc, 0, sizeof(struct ip_vs_service));

        svc->protocol = ur->protocol;
        svc->addr = ur->vaddr;
        svc->port = ur->vport;
        svc->fwmark = ur->vfwmark;
        svc->flags = ur->vs_flags;
        svc->timeout = ur->timeout * HZ;
        svc->netmask = ur->netmask;

        INIT_LIST_HEAD(&svc->destinations);
        svc->sched_lock = RW_LOCK_UNLOCKED;
        svc->stats.lock = SPIN_LOCK_UNLOCKED;

        /*
         *    Bind the scheduler
         */
        ret = ip_vs_bind_scheduler(svc, sched);
        if (ret) {
                goto out_err;
        }

        /*
         *    Update the virtual service counters
         */
        if (svc->port == FTPPORT)
                atomic_inc(&ip_vs_ftpsvc_counter);
        else if (svc->port == 0)
                atomic_inc(&ip_vs_nullsvc_counter);

        /*
         *    I'm the first user of the service
         */
        atomic_set(&svc->usecnt, 1);
        atomic_set(&svc->refcnt, 0);

        ip_vs_new_estimator(&svc->stats);
        ip_vs_num_services++;

        /*
         *    Hash the service into the service table
         */
        write_lock_bh(&__ip_vs_svc_lock);
        ip_vs_svc_hash(svc);
        write_unlock_bh(&__ip_vs_svc_lock);

        *svc_p = svc;
        return 0;

  out_err:
        if (svc)
                kfree(svc);
        ip_vs_scheduler_put(sched);
  out_mod_dec:
        MOD_DEC_USE_COUNT;
        return ret;
}


/*
 *      Edit a service and bind it with a new scheduler
 */
static int ip_vs_edit_service(struct ip_vs_service *svc,
                              struct ip_vs_rule_user *ur)
{
        struct ip_vs_scheduler *sched, *old_sched;
        int ret = 0;

        /*
         * Lookup the scheduler, by 'ur->sched_name'
         */
        sched = ip_vs_scheduler_get(ur->sched_name);
        if (sched == NULL) {
                IP_VS_INFO("Scheduler module ip_vs_%s.o not found\n",
                           ur->sched_name);
                return -ENOENT;
        }

        write_lock_bh(&__ip_vs_svc_lock);

        /*
         * Wait until all other svc users go away.
         */
        while (atomic_read(&svc->usecnt) > 1) {};

        /*
         * Set the flags and timeout value
         */
        svc->flags = ur->vs_flags | IP_VS_SVC_F_HASHED;
        svc->timeout = ur->timeout * HZ;
        svc->netmask = ur->netmask;

        old_sched = svc->scheduler;
        if (sched != old_sched) {
                /*
                 * Unbind the old scheduler
                 */
                if ((ret = ip_vs_unbind_scheduler(svc))) {
                        old_sched = sched;
                        goto out;
                }

                /*
                 * Bind the new scheduler
                 */
                if ((ret = ip_vs_bind_scheduler(svc, sched))) {
                        /*
                         * If ip_vs_bind_scheduler fails, restore the old
                         * scheduler.
                         * The main reason of failure is out of memory.
                         *
                         * The question is if the old scheduler can be
                         * restored all the time. TODO: if it cannot be
                         * restored some time, we must delete the service,
                         * otherwise the system may crash.
                         */
                        ip_vs_bind_scheduler(svc, old_sched);
                        old_sched = sched;
                }
        }

  out:
        write_unlock_bh(&__ip_vs_svc_lock);

        if (old_sched)
                ip_vs_scheduler_put(old_sched);

        return ret;
}


/*
 *  Delete a service from the service list
 *  The service must be unlinked, unlocked and not referenced!
 */
static void __ip_vs_del_service(struct ip_vs_service *svc)
{
        struct list_head *l;
        struct ip_vs_dest *dest;
        struct ip_vs_scheduler *old_sched;

        ip_vs_num_services--;
        ip_vs_kill_estimator(&svc->stats);

        /*
         *    Unbind scheduler
         */
        old_sched = svc->scheduler;
        ip_vs_unbind_scheduler(svc);
        if (old_sched && old_sched->module)
                __MOD_DEC_USE_COUNT(old_sched->module);

        /*
         *    Unlink the whole destination list
         */
        l = &svc->destinations;
        while (l->next != l) {
                dest = list_entry(l->next, struct ip_vs_dest, n_list);
                __ip_vs_unlink_dest(svc, dest, 0);
                __ip_vs_del_dest(dest);
        }

        /*
         *    Update the virtual service counters
         */
        if (svc->port == FTPPORT)
                atomic_dec(&ip_vs_ftpsvc_counter);
        else if (svc->port == 0)
                atomic_dec(&ip_vs_nullsvc_counter);

        /*
         *    Free the service if nobody refers to it
         */
        if (atomic_read(&svc->refcnt) == 0)
                kfree(svc);
        MOD_DEC_USE_COUNT;
}

/*
 *  Delete a service from the service list
 */
static int ip_vs_del_service(struct ip_vs_service *svc)
{
        if (svc == NULL)
                return -EEXIST;

        /*
         * Unhash it from the service table
         */
        write_lock_bh(&__ip_vs_svc_lock);

        ip_vs_svc_unhash(svc);

        /*
         * Wait until all the svc users go away.
         */
        while (atomic_read(&svc->usecnt) > 1) {};

        __ip_vs_del_service(svc);

        write_unlock_bh(&__ip_vs_svc_lock);

        return 0;
}


/*
 *  Flush all the virtual services
 */
static int ip_vs_flush(void)
{
        int idx;
        struct ip_vs_service *svc;
        struct list_head *l;

        /*
         * Flush the service table hashed by <protocol,addr,port>
         */
        for(idx = 0; idx < IP_VS_SVC_TAB_SIZE; idx++) {
                l = &ip_vs_svc_table[idx];
                while (l->next != l) {
                        svc = list_entry(l->next,struct ip_vs_service,s_list);
                        write_lock_bh(&__ip_vs_svc_lock);
                        ip_vs_svc_unhash(svc);
                        /*
                         * Wait until all the svc users go away.
                         */
                        while (atomic_read(&svc->usecnt) > 0) {};
                        __ip_vs_del_service(svc);
                        write_unlock_bh(&__ip_vs_svc_lock);
                }
        }

        /*
         * Flush the service table hashed by fwmark
         */
        for(idx = 0; idx < IP_VS_SVC_TAB_SIZE; idx++) {
                l = &ip_vs_svc_fwm_table[idx];
                while (l->next != l) {
                        svc = list_entry(l->next,struct ip_vs_service,f_list);
                        write_lock_bh(&__ip_vs_svc_lock);
                        ip_vs_svc_unhash(svc);
                        /*
                         * Wait until all the svc users go away.
                         */
                        while (atomic_read(&svc->usecnt) > 0) {};
                        __ip_vs_del_service(svc);
                        write_unlock_bh(&__ip_vs_svc_lock);
                }
        }

        return 0;
}


/*
 *  Zero counters in a service or all services
 */
static int ip_vs_zero_service(struct ip_vs_service *svc)
{
        struct list_head *l;
        struct ip_vs_dest *dest;

        write_lock_bh(&__ip_vs_svc_lock);
        list_for_each (l, &svc->destinations) {
                dest = list_entry(l, struct ip_vs_dest, n_list);
                __ip_vs_zero_stats(&dest->stats);
        }
        __ip_vs_zero_stats(&svc->stats);
        write_unlock_bh(&__ip_vs_svc_lock);
        return 0;
}

static int ip_vs_zero_all(void)
{
        int idx;
        struct list_head *l;
        struct ip_vs_service *svc;

        for(idx = 0; idx < IP_VS_SVC_TAB_SIZE; idx++) {
                list_for_each (l, &ip_vs_svc_table[idx]) {
                        svc = list_entry(l, struct ip_vs_service, s_list);
                        ip_vs_zero_service(svc);
                }
        }

        for(idx = 0; idx < IP_VS_SVC_TAB_SIZE; idx++) {
                list_for_each (l, &ip_vs_svc_fwm_table[idx]) {
                        svc = list_entry(l, struct ip_vs_service, f_list);
                        ip_vs_zero_service(svc);
                }
        }

        __ip_vs_zero_stats(&ip_vs_stats);
        return 0;
}


static int ip_vs_sysctl_defense_mode(ctl_table *ctl, int write,
        struct file * filp, void *buffer, size_t *lenp)
{
        int *valp = ctl->data;
        int val = *valp;
        int ret;

        ret = proc_dointvec(ctl, write, filp, buffer, lenp);
        if (write && (*valp != val)) {
                if ((*valp < 0) || (*valp > 3)) {
                        /* Restore the correct value */
                        *valp = val;
                } else {
                        local_bh_disable();
                        update_defense_level();
                        local_bh_enable();
                }
        }
        return ret;
}


/*
 *      IPVS sysctl table
 */
struct ip_vs_sysctl_table {
        struct ctl_table_header *sysctl_header;
        ctl_table vs_vars[NET_IPV4_VS_LAST];
        ctl_table vs_dir[2];
        ctl_table ipv4_dir[2];
        ctl_table root_dir[2];
};


static struct ip_vs_sysctl_table ipv4_vs_table = {
        NULL,
        {{NET_IPV4_VS_AMEMTHRESH, "amemthresh",
          &sysctl_ip_vs_amemthresh, sizeof(int), 0644, NULL,
          &proc_dointvec},
#ifdef CONFIG_IP_VS_DEBUG
         {NET_IPV4_VS_DEBUG_LEVEL, "debug_level",
          &sysctl_ip_vs_debug_level, sizeof(int), 0644, NULL,
          &proc_dointvec},
#endif
         {NET_IPV4_VS_AMDROPRATE, "am_droprate",
          &sysctl_ip_vs_am_droprate, sizeof(int), 0644, NULL,
          &proc_dointvec},
         {NET_IPV4_VS_DROP_ENTRY, "drop_entry",
          &sysctl_ip_vs_drop_entry, sizeof(int), 0644, NULL,
          &ip_vs_sysctl_defense_mode},
         {NET_IPV4_VS_DROP_PACKET, "drop_packet",
          &sysctl_ip_vs_drop_packet, sizeof(int), 0644, NULL,
          &ip_vs_sysctl_defense_mode},
         {NET_IPV4_VS_SECURE_TCP, "secure_tcp",
          &sysctl_ip_vs_secure_tcp, sizeof(int), 0644, NULL,
          &ip_vs_sysctl_defense_mode},
         {NET_IPV4_VS_TO_ES, "timeout_established",
          &vs_timeout_table_dos.timeout[IP_VS_S_ESTABLISHED],
          sizeof(int), 0644, NULL, &proc_dointvec_jiffies},
         {NET_IPV4_VS_TO_SS, "timeout_synsent",
          &vs_timeout_table_dos.timeout[IP_VS_S_SYN_SENT],
          sizeof(int), 0644, NULL, &proc_dointvec_jiffies},
         {NET_IPV4_VS_TO_SR, "timeout_synrecv",
          &vs_timeout_table_dos.timeout[IP_VS_S_SYN_RECV],
          sizeof(int), 0644, NULL, &proc_dointvec_jiffies},
         {NET_IPV4_VS_TO_FW, "timeout_finwait",
          &vs_timeout_table_dos.timeout[IP_VS_S_FIN_WAIT],
          sizeof(int), 0644, NULL, &proc_dointvec_jiffies},
         {NET_IPV4_VS_TO_TW, "timeout_timewait",
          &vs_timeout_table_dos.timeout[IP_VS_S_TIME_WAIT],
          sizeof(int), 0644, NULL, &proc_dointvec_jiffies},
         {NET_IPV4_VS_TO_CL, "timeout_close",
          &vs_timeout_table_dos.timeout[IP_VS_S_CLOSE],
          sizeof(int), 0644, NULL, &proc_dointvec_jiffies},
         {NET_IPV4_VS_TO_CW, "timeout_closewait",
          &vs_timeout_table_dos.timeout[IP_VS_S_CLOSE_WAIT],
          sizeof(int), 0644, NULL, &proc_dointvec_jiffies},
         {NET_IPV4_VS_TO_LA, "timeout_lastack",
          &vs_timeout_table_dos.timeout[IP_VS_S_LAST_ACK],
          sizeof(int), 0644, NULL, &proc_dointvec_jiffies},
         {NET_IPV4_VS_TO_LI, "timeout_listen",
          &vs_timeout_table_dos.timeout[IP_VS_S_LISTEN],
          sizeof(int), 0644, NULL, &proc_dointvec_jiffies},
         {NET_IPV4_VS_TO_SA, "timeout_synack",
          &vs_timeout_table_dos.timeout[IP_VS_S_SYNACK],
          sizeof(int), 0644, NULL, &proc_dointvec_jiffies},
         {NET_IPV4_VS_TO_UDP, "timeout_udp",
          &vs_timeout_table_dos.timeout[IP_VS_S_UDP],
          sizeof(int), 0644, NULL, &proc_dointvec_jiffies},
         {NET_IPV4_VS_TO_ICMP, "timeout_icmp",
          &vs_timeout_table_dos.timeout[IP_VS_S_ICMP],
          sizeof(int), 0644, NULL, &proc_dointvec_jiffies},
         {NET_IPV4_VS_CACHE_BYPASS, "cache_bypass",
          &sysctl_ip_vs_cache_bypass, sizeof(int), 0644, NULL,
          &proc_dointvec},
         {NET_IPV4_VS_EXPIRE_NODEST_CONN, "expire_nodest_conn",
          &sysctl_ip_vs_expire_nodest_conn, sizeof(int), 0644, NULL,
          &proc_dointvec},
         {NET_IPV4_VS_SYNC_THRESHOLD, "sync_threshold",
          &sysctl_ip_vs_sync_threshold, sizeof(int), 0644, NULL,
          &proc_dointvec},
         {NET_IPV4_VS_NAT_ICMP_SEND, "nat_icmp_send",
          &sysctl_ip_vs_nat_icmp_send, sizeof(int), 0644, NULL,
          &proc_dointvec},
         {0}},
        {{NET_IPV4_VS, "vs", NULL, 0, 0555, ipv4_vs_table.vs_vars},
         {0}},
        {{NET_IPV4, "ipv4", NULL, 0, 0555, ipv4_vs_table.vs_dir},
         {0}},
        {{CTL_NET, "net", NULL, 0, 0555, ipv4_vs_table.ipv4_dir},
         {0}}
};


/*
 *      Write the contents of the VS rule table to a PROCfs file.
 *      (It is kept just for backward compatibility)
 */
static inline char *ip_vs_fwd_name(unsigned flags)
{
        char *fwd;

        switch (flags & IP_VS_CONN_F_FWD_MASK) {
        case IP_VS_CONN_F_LOCALNODE:
                fwd = "Local";
                break;
        case IP_VS_CONN_F_TUNNEL:
                fwd = "Tunnel";
                break;
        case IP_VS_CONN_F_DROUTE:
                fwd = "Route";
                break;
        default:
                fwd = "Masq";
        }
        return fwd;
}

static int ip_vs_get_info(char *buf, char **start, off_t offset, int length)
{
        int len=0;
        off_t pos=0;
        char temp[64], temp2[32];
        int idx;
        struct ip_vs_service *svc;
        struct ip_vs_dest *dest;
        struct list_head *l, *e, *p, *q;

        /*
         * Note: since the length of the buffer is usually the multiple
         * of 512, it is good to use fixed record of the divisor of 512,
         * so that records won't be truncated at buffer boundary.
         */
        pos = 192;
        if (pos > offset) {
                sprintf(temp,
                        "IP Virtual Server version %d.%d.%d (size=%d)",
                        NVERSION(IP_VS_VERSION_CODE), IP_VS_CONN_TAB_SIZE);
                len += sprintf(buf+len, "%-63s\n", temp);
                len += sprintf(buf+len, "%-63s\n",
                               "Prot LocalAddress:Port Scheduler Flags");
                len += sprintf(buf+len, "%-63s\n",
                               "  -> RemoteAddress:Port Forward Weight ActiveConn InActConn");
        }

        read_lock_bh(&__ip_vs_svc_lock);

        /* print the service table hashed by <protocol,addr,port> */
        for (idx = 0; idx < IP_VS_SVC_TAB_SIZE; idx++) {
                l = &ip_vs_svc_table[idx];
                for (e=l->next; e!=l; e=e->next) {
                        svc = list_entry(e, struct ip_vs_service, s_list);
                        pos += 64;
                        if (pos > offset) {
                                if (svc->flags & IP_VS_SVC_F_PERSISTENT)
                                        sprintf(temp2, "persistent %d %08X",
                                                svc->timeout,
                                                ntohl(svc->netmask));
                                else
                                        temp2[0] = '\0';

                                sprintf(temp, "%s  %08X:%04X %s %s",
                                        ip_vs_proto_name(svc->protocol),
                                        ntohl(svc->addr),
                                        ntohs(svc->port),
                                        svc->scheduler->name, temp2);
                                len += sprintf(buf+len, "%-63s\n", temp);
                                if (len >= length)
                                        goto done;
                        }

                        p = &svc->destinations;
                        for (q=p->next; q!=p; q=q->next) {
                                dest = list_entry(q, struct ip_vs_dest, n_list);
                                pos += 64;
                                if (pos <= offset)
                                        continue;
                                sprintf(temp,
                                        "  -> %08X:%04X      %-7s %-6d %-10d %-10d",
                                        ntohl(dest->addr),
                                        ntohs(dest->port),
                                        ip_vs_fwd_name(atomic_read(&dest->conn_flags)),
                                        atomic_read(&dest->weight),
                                        atomic_read(&dest->activeconns),
                                        atomic_read(&dest->inactconns));
                                len += sprintf(buf+len, "%-63s\n", temp);
                                if (len >= length)
                                        goto done;
                        }
                }
        }

        /* print the service table hashed by fwmark */
        for (idx = 0; idx < IP_VS_SVC_TAB_SIZE; idx++) {
                l = &ip_vs_svc_fwm_table[idx];
                for (e=l->next; e!=l; e=e->next) {
                        svc = list_entry(e, struct ip_vs_service, f_list);
                        pos += 64;
                        if (pos > offset) {
                                if (svc->flags & IP_VS_SVC_F_PERSISTENT)
                                        sprintf(temp2, "persistent %d %08X",
                                                svc->timeout,
                                                ntohl(svc->netmask));
                                else
                                        temp2[0] = '\0';

                                sprintf(temp, "FWM  %08X %s %s",
                                        svc->fwmark,
                                        svc->scheduler->name, temp2);
                                len += sprintf(buf+len, "%-63s\n", temp);
                                if (len >= length)
                                        goto done;
                        }

                        p = &svc->destinations;
                        for (q=p->next; q!=p; q=q->next) {
                                dest = list_entry(q, struct ip_vs_dest, n_list);
                                pos += 64;
                                if (pos <= offset)
                                        continue;
                                sprintf(temp,
                                        "  -> %08X:%04X      %-7s %-6d %-10d %-10d",
                                        ntohl(dest->addr),
                                        ntohs(dest->port),
                                        ip_vs_fwd_name(atomic_read(&dest->conn_flags)),
                                        atomic_read(&dest->weight),
                                        atomic_read(&dest->activeconns),
                                        atomic_read(&dest->inactconns));
                                len += sprintf(buf+len, "%-63s\n", temp);
                                if (len >= length)
                                        goto done;
                        }
                }
        }

  done:
        read_unlock_bh(&__ip_vs_svc_lock);

        *start = buf+len-(pos-offset);          /* Start of wanted data */
        len = pos-offset;
        if (len > length)
                len = length;
        if (len < 0)
                len = 0;
        return len;
}


struct ip_vs_stats ip_vs_stats;

static int
ip_vs_stats_get_info(char *buf, char **start, off_t offset, int length)
{
        int len=0;
        off_t pos=0;
        char temp[64];

        pos += 320;
        if (pos > offset) {
                len += sprintf(buf+len, "%-63s\n%-63s\n",
/*                              01234567 01234567 01234567 0123456701234567 0123456701234567 */
                               "   Total Incoming Outgoing         Incoming         Outgoing",
                               "   Conns  Packets  Packets            Bytes            Bytes");

                spin_lock_bh(&ip_vs_stats.lock);
                sprintf(temp, "%8X %8X %8X %8X%08X %8X%08X",
                        ip_vs_stats.conns,
                        ip_vs_stats.inpkts,
                        ip_vs_stats.outpkts,
                        (__u32)(ip_vs_stats.inbytes>>32),
                        (__u32)ip_vs_stats.inbytes,
                        (__u32)(ip_vs_stats.outbytes>>32),
                        (__u32)ip_vs_stats.outbytes);
                len += sprintf(buf+len, "%-62s\n\n", temp);

                len += sprintf(buf+len, "%-63s\n",
/*                              01234567 01234567 01234567 0123456701234567 0123456701234567 */
                               " Conns/s   Pkts/s   Pkts/s          Bytes/s          Bytes/s");
                sprintf(temp, "%8X %8X %8X %16X %16X",
                        ip_vs_stats.cps,
                        ip_vs_stats.inpps,
                        ip_vs_stats.outpps,
                        ip_vs_stats.inbps,
                        ip_vs_stats.outbps);
                len += sprintf(buf+len, "%-63s\n", temp);

                spin_unlock_bh(&ip_vs_stats.lock);
        }

        *start = buf+len-(pos-offset);          /* Start of wanted data */
        len = pos-offset;
        if (len > length)
                len = length;
        if (len < 0)
                len = 0;
        return len;
}


/*
 * Set timeout values for tcp tcpfin udp in the vs_timeout_table.
 */
static int ip_vs_set_timeouts(struct ip_vs_rule_user *u)
{
        IP_VS_DBG(2, "Setting timeout tcp:%d tcpfin:%d udp:%d\n",
                  u->tcp_timeout,
                  u->tcp_fin_timeout,
                  u->udp_timeout);

        if (u->tcp_timeout) {
                vs_timeout_table.timeout[IP_VS_S_ESTABLISHED]
                        = u->tcp_timeout * HZ;
        }

        if (u->tcp_fin_timeout) {
                vs_timeout_table.timeout[IP_VS_S_FIN_WAIT]
                        = u->tcp_fin_timeout * HZ;
        }

        if (u->udp_timeout) {
                vs_timeout_table.timeout[IP_VS_S_UDP]
                        = u->udp_timeout * HZ;
        }
        return 0;
}


static int
do_ip_vs_set_ctl(struct sock *sk, int cmd, void *user, unsigned int len)
{
        int ret;
        struct ip_vs_rule_user *urule;
        struct ip_vs_service *svc = NULL;

        if (!capable(CAP_NET_ADMIN))
                return -EPERM;

        /*
         * Check the size of mm, no overflow...
         * len > 128000 is a sanity check.
         */
        if (len < sizeof(struct ip_vs_rule_user)) {
                IP_VS_ERR("set_ctl: len %u < %u\n",
                          len, sizeof(struct ip_vs_rule_user));
                return -EINVAL;
        } else if (len > 128000) {
                IP_VS_ERR("set_ctl: len %u > 128000\n", len);
                return -EINVAL;
        } else if ((urule = kmalloc(len, GFP_KERNEL)) == NULL) {
                IP_VS_ERR("set_ctl: no mem for len %u\n", len);
                return -ENOMEM;
        } else if (copy_from_user(urule, user, len) != 0) {
                ret = -EFAULT;
                goto out_free;
        }

        MOD_INC_USE_COUNT;
        if (down_interruptible(&__ip_vs_mutex)) {
                ret = -ERESTARTSYS;
                goto out_dec;
        }

        if (cmd == IP_VS_SO_SET_FLUSH) {
                /* Flush the virtual service */
                ret = ip_vs_flush();
                goto out_unlock;
        } else if (cmd == IP_VS_SO_SET_TIMEOUTS) {
                /* Set timeout values for (tcp tcpfin udp) */
                ret = ip_vs_set_timeouts(urule);
                goto out_unlock;
        } else if (cmd == IP_VS_SO_SET_STARTDAEMON) {
                ret = start_sync_thread(urule->state, urule->mcast_ifn);
                goto out_unlock;
        } else if (cmd == IP_VS_SO_SET_STOPDAEMON) {
                ret = stop_sync_thread();
                goto out_unlock;
        } else if (cmd == IP_VS_SO_SET_ZERO) {
                /* if no service address is set, zero counters in all */
                if (!urule->vfwmark && !urule->vaddr && !urule->vport) {
                        ret = ip_vs_zero_all();
                        goto out_unlock;
                }
        }

        /*
         * Check for valid protocol: TCP or UDP. Even for fwmark!=0
         */
        if (urule->protocol!=IPPROTO_TCP && urule->protocol!=IPPROTO_UDP) {
                IP_VS_INFO("vs_ctl: invalid protocol: %d %d.%d.%d.%d:%d %s",
                           ntohs(urule->protocol), NIPQUAD(urule->vaddr),
                           ntohs(urule->vport), urule->sched_name);
                ret = -EFAULT;
                goto out_unlock;
        }

        /*
         * Lookup the exact service by <protocol, vaddr, vport> or fwmark
         */
        if (urule->vfwmark == 0)
                svc = __ip_vs_service_get(urule->protocol,
                                          urule->vaddr, urule->vport);
        else
                svc = __ip_vs_svc_fwm_get(urule->vfwmark);

        if (cmd != IP_VS_SO_SET_ADD
            && (svc == NULL || svc->protocol != urule->protocol)) {
                ret = -ESRCH;
                goto out_unlock;
        }

        switch (cmd) {
        case IP_VS_SO_SET_ADD:
                if (svc != NULL)
                        ret = -EEXIST;
                else
                        ret = ip_vs_add_service(urule, &svc);
                break;
        case IP_VS_SO_SET_EDIT:
                ret = ip_vs_edit_service(svc, urule);
                break;
        case IP_VS_SO_SET_DEL:
                ret = ip_vs_del_service(svc);
                if (!ret)
                        goto out_unlock;
                break;
        case IP_VS_SO_SET_ADDDEST:
                ret = ip_vs_add_dest(svc, urule);
                break;
        case IP_VS_SO_SET_EDITDEST:
                ret = ip_vs_edit_dest(svc, urule);
                break;
        case IP_VS_SO_SET_DELDEST:
                ret = ip_vs_del_dest(svc, urule);
                break;
        case IP_VS_SO_SET_ZERO:
                ret = ip_vs_zero_service(svc);
                break;
        default:
                ret = -EINVAL;
        }

        if (svc)
                ip_vs_service_put(svc);

  out_unlock:
        up(&__ip_vs_mutex);
  out_dec:
        MOD_DEC_USE_COUNT;
  out_free:
        kfree(urule);
        return ret;
}


static inline void
__ip_vs_copy_stats(struct ip_vs_stats_user *dst, struct ip_vs_stats *src)
{
        spin_lock_bh(&src->lock);
        memcpy(dst, src, (char*)&src->lock - (char*)src);
        spin_unlock_bh(&src->lock);
}

static inline int
__ip_vs_get_service_entries(const struct ip_vs_get_services *get,
                            struct ip_vs_get_services *uptr)
{
        int idx, count=0;
        struct ip_vs_service *svc;
        struct list_head *l;
        struct ip_vs_service_user entry;
        int ret = 0;

        for (idx = 0; idx < IP_VS_SVC_TAB_SIZE; idx++) {
                list_for_each (l, &ip_vs_svc_table[idx]) {
                        if (count >= get->num_services)
                                goto out;
                        svc = list_entry(l, struct ip_vs_service, s_list);
                        entry.protocol = svc->protocol;
                        entry.addr = svc->addr;
                        entry.port = svc->port;
                        entry.fwmark = svc->fwmark;
                        strcpy(entry.sched_name, svc->scheduler->name);
                        entry.flags = svc->flags;
                        entry.timeout = svc->timeout / HZ;
                        entry.netmask = svc->netmask;
                        entry.num_dests = svc->num_dests;
                        __ip_vs_copy_stats(&entry.stats, &svc->stats);
                        if (copy_to_user(&uptr->entrytable[count],
                                         &entry, sizeof(entry))) {
                                ret = -EFAULT;
                                goto out;
                        }
                        count++;
                }
        }

        for (idx = 0; idx < IP_VS_SVC_TAB_SIZE; idx++) {
                list_for_each (l, &ip_vs_svc_fwm_table[idx]) {
                        if (count >= get->num_services)
                                goto out;
                        svc = list_entry(l, struct ip_vs_service, f_list);
                        entry.protocol = svc->protocol;
                        entry.addr = svc->addr;
                        entry.port = svc->port;
                        entry.fwmark = svc->fwmark;
                        strcpy(entry.sched_name, svc->scheduler->name);
                        entry.flags = svc->flags;
                        entry.timeout = svc->timeout / HZ;
                        entry.netmask = svc->netmask;
                        entry.num_dests = svc->num_dests;
                        __ip_vs_copy_stats(&entry.stats, &svc->stats);
                        if (copy_to_user(&uptr->entrytable[count],
                                         &entry, sizeof(entry))) {
                                ret = -EFAULT;
                                goto out;
                        }
                        count++;
                }
        }
 out:
        return ret;
}

static inline int
__ip_vs_get_dest_entries(const struct ip_vs_get_dests *get,
                         struct ip_vs_get_dests *uptr)
{
        struct ip_vs_service *svc;
        int ret = 0;

        if (get->fwmark)
                svc = __ip_vs_svc_fwm_get(get->fwmark);
        else
                svc = __ip_vs_service_get(get->protocol,
                                          get->addr, get->port);
        if (svc) {
                int count = 0;
                struct ip_vs_dest *dest;
                struct list_head *l, *e;
                struct ip_vs_dest_user entry;

                l = &svc->destinations;
                for (e=l->next; e!=l; e=e->next) {
                        if (count >= get->num_dests)
                                break;
                        dest = list_entry(e, struct ip_vs_dest, n_list);
                        entry.addr = dest->addr;
                        entry.port = dest->port;
                        entry.flags = atomic_read(&dest->conn_flags);
                        entry.weight = atomic_read(&dest->weight);
                        entry.activeconns = atomic_read(&dest->activeconns);
                        entry.inactconns = atomic_read(&dest->inactconns);
                        __ip_vs_copy_stats(&entry.stats, &dest->stats);
                        if (copy_to_user(&uptr->entrytable[count],
                                         &entry, sizeof(entry))) {
                                ret = -EFAULT;
                                break;
                        }
                        count++;
                }
                ip_vs_service_put(svc);
        } else
                ret = -ESRCH;
        return ret;
}

static inline void
__ip_vs_get_timeouts(struct ip_vs_timeout_user *u)
{
        u->tcp_timeout = vs_timeout_table.timeout[IP_VS_S_ESTABLISHED] / HZ;
        u->tcp_fin_timeout = vs_timeout_table.timeout[IP_VS_S_FIN_WAIT] / HZ;
        u->udp_timeout = vs_timeout_table.timeout[IP_VS_S_UDP] / HZ;
}

static int
do_ip_vs_get_ctl(struct sock *sk, int cmd, void *user, int *len)
{
        int ret = 0;

        if (!capable(CAP_NET_ADMIN))
                return -EPERM;

        if (down_interruptible(&__ip_vs_mutex))
                return -ERESTARTSYS;

        switch (cmd) {
        case IP_VS_SO_GET_VERSION:
        {
                char buf[64];

                sprintf(buf, "IP Virtual Server version %d.%d.%d (size=%d)",
                        NVERSION(IP_VS_VERSION_CODE), IP_VS_CONN_TAB_SIZE);
                if (*len < strlen(buf)+1) {
                        ret = -EINVAL;
                        goto out;
                }
                if (copy_to_user(user, buf, strlen(buf)+1) != 0) {
                        ret = -EFAULT;
                        goto out;
                }
                *len = strlen(buf)+1;
        }
        break;

        case IP_VS_SO_GET_INFO:
        {
                struct ip_vs_getinfo info;
                info.version = IP_VS_VERSION_CODE;
                info.size = IP_VS_CONN_TAB_SIZE;
                info.num_services = ip_vs_num_services;
                if (copy_to_user(user, &info, sizeof(info)) != 0)
                        ret = -EFAULT;
        }
        break;

        case IP_VS_SO_GET_SERVICES:
        {
                struct ip_vs_get_services get;

                if (*len < sizeof(get)) {
                        IP_VS_ERR("length: %u < %u\n", *len, sizeof(get));
                        ret = -EINVAL;
                        goto out;
                }
                if (copy_from_user(&get, user, sizeof(get))) {
                        ret = -EFAULT;
                        goto out;
                }
                if (*len != (sizeof(get)+sizeof(struct ip_vs_service_user)*get.num_services)) {
                        IP_VS_ERR("length: %u != %u\n", *len,
                                  sizeof(get)+sizeof(struct ip_vs_service_user)*get.num_services);
                        ret = -EINVAL;
                        goto out;
                }
                ret = __ip_vs_get_service_entries(&get, user);
        }
        break;

        case IP_VS_SO_GET_SERVICE:
        {
                struct ip_vs_service_user get;
                struct ip_vs_service *svc;

                if (*len != sizeof(get)) {
                        IP_VS_ERR("length: %u != %u\n", *len, sizeof(get));
                        ret = -EINVAL;
                        goto out;
                }
                if (copy_from_user(&get, user, sizeof(get))) {
                        ret = -EFAULT;
                        goto out;
                }

                if (get.fwmark)
                        svc = __ip_vs_svc_fwm_get(get.fwmark);
                else
                        svc = __ip_vs_service_get(get.protocol,
                                                  get.addr, get.port);
                if (svc) {
                        strcpy(get.sched_name, svc->scheduler->name);
                        get.flags = svc->flags;
                        get.timeout = svc->timeout / HZ;
                        get.netmask = svc->netmask;
                        get.num_dests = svc->num_dests;
                        __ip_vs_copy_stats(&get.stats, &svc->stats);
                        if (copy_to_user(user, &get, *len) != 0)
                                ret = -EFAULT;
                        ip_vs_service_put(svc);
                } else
                        ret = -ESRCH;
        }
        break;

        case IP_VS_SO_GET_DESTS:
        {
                struct ip_vs_get_dests get;

                if (*len < sizeof(get)) {
                        IP_VS_ERR("length: %u < %u\n", *len, sizeof(get));
                        ret = -EINVAL;
                        goto out;
                }
                if (copy_from_user(&get, user, sizeof(get))) {
                        ret = -EFAULT;
                        goto out;
                }
                if (*len != (sizeof(get) +
                             sizeof(struct ip_vs_dest_user)*get.num_dests)) {
                        IP_VS_ERR("length: %u != %u\n", *len,
                                  sizeof(get)+sizeof(struct ip_vs_dest_user)*get.num_dests);
                        ret = -EINVAL;
                        goto out;
                }
                ret = __ip_vs_get_dest_entries(&get, user);
        }
        break;

        case IP_VS_SO_GET_TIMEOUTS:
        {
                struct ip_vs_timeout_user u;

                if (*len < sizeof(u)) {
                        IP_VS_ERR("length: %u < %u\n", *len, sizeof(u));
                        ret = -EINVAL;
                        goto out;
                }
                __ip_vs_get_timeouts(&u);
                if (copy_to_user(user, &u, sizeof(u)) != 0)
                        ret = -EFAULT;
        }
        break;

        case IP_VS_SO_GET_DAEMON:
        {
                struct ip_vs_daemon_user u;

                if (*len < sizeof(u)) {
                        IP_VS_ERR("length: %u < %u\n", *len, sizeof(u));
                        ret = -EINVAL;
                        goto out;
                }
                u.state = ip_vs_sync_state;
                strcpy(u.mcast_ifn, ip_vs_mcast_ifn);
                if (copy_to_user(user, &u, sizeof(u)) != 0)
                        ret = -EFAULT;
        }
        break;

        default:
                ret = -EINVAL;
        }

  out:
        up(&__ip_vs_mutex);
        return ret;
}


static struct nf_sockopt_ops ip_vs_sockopts = {
        { NULL, NULL }, PF_INET,
        IP_VS_BASE_CTL, IP_VS_SO_SET_MAX+1, do_ip_vs_set_ctl,
        IP_VS_BASE_CTL, IP_VS_SO_GET_MAX+1, do_ip_vs_get_ctl
};


int ip_vs_control_init(void)
{
        int ret;
        int idx;

        EnterFunction(2);

        ret = nf_register_sockopt(&ip_vs_sockopts);
        if (ret) {
                IP_VS_ERR("cannot register sockopt.\n");
                return ret;
        }

        proc_net_create("ip_vs", 0, ip_vs_get_info);
        proc_net_create("ip_vs_stats", 0, ip_vs_stats_get_info);

        ipv4_vs_table.sysctl_header =
                register_sysctl_table(ipv4_vs_table.root_dir, 0);
        /*
         * Initilize ip_vs_svc_table, ip_vs_svc_fwm_table, ip_vs_rtable,
         * ip_vs_schedulers.
         */
        for(idx = 0; idx < IP_VS_SVC_TAB_SIZE; idx++)  {
                INIT_LIST_HEAD(&ip_vs_svc_table[idx]);
                INIT_LIST_HEAD(&ip_vs_svc_fwm_table[idx]);
        }
        for(idx = 0; idx < IP_VS_RTAB_SIZE; idx++)  {
                INIT_LIST_HEAD(&ip_vs_rtable[idx]);
        }

        memset(&ip_vs_stats, 0, sizeof(ip_vs_stats));
        ip_vs_stats.lock = SPIN_LOCK_UNLOCKED;
        ip_vs_new_estimator(&ip_vs_stats);

        /* Hook the defense timer */
        init_timer(&defense_timer);
        defense_timer.function = defense_timer_handler;
        defense_timer.expires = jiffies + DEFENSE_TIMER_PERIOD;
        add_timer(&defense_timer);

        LeaveFunction(2);
        return 0;
}

void ip_vs_control_cleanup(void)
{
        EnterFunction(2);
        ip_vs_trash_cleanup();
        del_timer_sync(&defense_timer);
        ip_vs_kill_estimator(&ip_vs_stats);
        unregister_sysctl_table(ipv4_vs_table.sysctl_header);
        proc_net_remove("ip_vs_stats");
        proc_net_remove("ip_vs");
        nf_unregister_sockopt(&ip_vs_sockopts);
        LeaveFunction(2);
}

---